The field of this invention relates to cellular communication systems and more particularly to voice recognition systems used within cellular communication systems.
Cellular systems using voice recognition for number dialing are known. One such system was that taught by Bareis et al. in U.S. Pat. No. 5,297,183. Such systems typically rely on a voice recognition system operably interconnected with a cellular switch located at a mobile telephone switching office (MTSO) and, in turn, accessed through the use of a special, voice dial activation sequence (e.g., * # "send").
A memory is typically associated with the voice recognition system. The memory is used to store a speech profile of individual users. The identity of an individual user is transferred to the voice recognition system during call set-up. The identity of the user allows the voice recognition system, by reference to a voice profile of a particular user, to more accurately interpret the spoken words of an individual user.
To use the cellular voice recognition system, a user activates the cellular phone and presses the voice dial sequence. In response, a MTSO operating through a nearby cellular base station allocates a radio frequency (RF) traffic channel between the base station and user. The MTSO also allocates a wireline traffic channel between the MTSO and voice recognition unit.
Upon completion of a voice path between the user and voice recognition unit, the user speaks a key word such as "dial" followed by a sequence of spoken numbers identifying a communication target. The voice recognition system converts the spoken words into digits and formats the digits into a call request to the communication target under an appropriate telephone protocol (e.g., feature group D (fg-d)) understood by the cellular switch of the MTSO. The call request is transferred back to the originating MTSO which, in turn, completes the call.
As an alternative to reciting a sequence of numbers for access to a communication target, a user may store a number sequence under a name such as "home" or "office", or "Bob", or "Mary". The user stores the sequence by first reciting a number sequence followed by the word "store" and a name. Following storage of a name and associated access number, the user simply speaks the word "call" followed by the name. The voice recognition system responds by retrieving the number from memory and transferring a call access request to an originating switch.
Call completion may be accomplished under either of two possible scenarios. Typically, the call is completed directly from the voice recognition system to the communication target, leaving the voice recognition system within the voice path between the cellular caller and communication target. Alternatively, the MTSO could re-route the call path directly from the cellular caller to the communication target.
While voice recognition systems have worked well, the prior art has limited the use of such systems to the subscriber/ cellular system interface at the MTSO. The use of such systems in the automotive context has significantly enhanced the safety of cellular phones used in automobiles by allowing a driver of an automobile to dial without taking his/her eyes off the road. Directory assisted calls have also reduced risks of cellular calls in recent years by allowing automatic call completion through apparatus associated with the directory assistance database.
Directory assistance, on the other hand, is a service that is typically associated with a local public switch telephone network (PSTN). Because directory assistance is located within the PSTN, it is typically the PSTN which completes the call connection of the directory assisted call.
Where a directory assisted call is from a first cellular user to a second party, the directory assisted call is routed through a cellular base station of the first user to a PSTN switch of the directory assistance system, and then to the second party. Calls to directory assistance are typically routed through a switch of the PSTN because the PSTN cannot reroute calls through the cellular system due to differing signalling protocols and also because of a desire on the part of owners of the PSTN to retain the revenue associated with such routing within the PSTN. Further, since the PSTN completes the call connection, the cellular system does not have a call record of such call until such time as the PSTN forwards a bill. When the PSTN forwards a bill for the call, the time use records of the cellular system can be matched with the PSTN line charges and a bill sent to the cellular subscriber. Because of the delay in billing from the PSTN, a cellular subscriber may receive a bill for PSTN line charges a month or more after the cellular subscriber has paid for the cellular air-time associated with the call. Because of the importance of billing efficiency in communication systems, a need exists for a means of automatically routing directory assisted calls from within the cellular system. Such means is important not only from the point of view of timely billing to the subscriber, but also because of a need to maximize revenue within an originating cellular system. The cellular system, as the original service provider, should have the first right of providing customer support services such as call forwarding and automatic call completion.